1. Field of the Invention
This invention relates to a power take-off unit utilizing the propeller shaft of an automobile or truck as its power source. More specifically, the invention relates to a power take-off unit for driving a hydraulic pump that attaches directly and rigidly to the differential gear housing of the rear axle.
2. Description of the Prior Art
Many trucks and other vehicles now in use for highway or road work are adapted to carry hydraulically operated equipment of various types for numerous purposes. The pump for operating this type of equipment is usually driven from the front end of the engine compartment as exemplified in U.S. Pat. No. 3,828,878 wherein a front mounted power take-off unit is required.
Vehicle power take-off units from locations other than the front engine compartment have been suggested and used in the past in a variety of applications. Thus it is generally known to provide for power take-off from various locations in the vehicle including: from openings in the transmission or gear, case, e.g. U.S. Pat. Nos. 3,540,297, 3,548,667, 2,100,677 and 2,100,678; from the rear of the transmission before the drive train, e.g. U.S. Pat. No. 3,296,895; in the drive train between the transmission and differential, e.g. U.S. Pat. Nos. 3,049,929 and 3,982,443; from the rear of the differential, e.g. U.S. Pat. No. 3,986,576; from the transmission via a separate drive train, e.g. U.S. Pat. Nos. 2,817,408 and 2,464,059; and from worm or bevel gears attached to the drive train, e.g. U.S. Pat. Nos. 1,915,015 and 1,786,067. However, these power take-off units are directed to supplying mechanical motion without a hydraulic pump and none represents a unit that can be readily and economically attached to a conventional truck or automobile in order to operate hydraulic equipment and the like.